Url settings when deploy GitLab-CE by docker image

Question

I'd like to know what are correct value for Gitlab-CE docker image's external_url and registry_external_url

Desired final status:

1. Docker running on 192.168.1.21, ports 19022 19080 19443 19050 for ssh, web and container registry.
2. Url for public network access is https://gitlab.k-m.com:21444 (just for example, 80/443 is disabled by ISP)
3. Router will forward connection from port 21444 to SWAG (for acquiring certs and reverse proxy), and SWAG has config like:

listen 443 ssl http2;
listen [::]:443 ssl http2;
server_name gitlab.*;
include /config/nginx/ssl.conf;
location / {
    proxy_pass https://192.168.1.21:19080;
}

Problems I meet:

1. If i set external_url as https one, gitlab will try to acquire certs, that's what i want SWAG to do
2. If i set external_url as 192.168.1.21:19080, i don't how to set port forwarding in docker run
3. Currently, i set localhost:80 for external_url, and set 19080:80 in port forwarding, but
   1. localhost shows everywhere in GitLab's web ui
   2. edit runner it automatically redirect to http://localhost/groups/mygroup/-/runners/1
   3. https://gitlab.k-m.com:21444 shows ERR_CONNECTION_CLOSED

external_url 'http://localhost:80'; registry_external_url 'http://localhost:5050';

I believe i misunderstand the meanings of these fields, but i cannot find what is correct in offical document for my scenario, could you help to guide me